No one, so what is the secondary argument?
But is incorrect to deny that this issue was the root cause of the conflict. And more incorrect to conclude that the outcome was merely to make illegal the consideration of persons as chattel. The Federal form of the government and the striking change away from the constitutional reservation of rights by the states was the result. This was Adams and Hamilton versus Jefferson played out by their grandchildren, and probably those Jacksonian as well. Sam Houston strongly opposed secession.
This country was taken over (effectively) by an armed coup by the Lincoln Republicans and abolitionists and northeastern industrialists, and the southern states decided to leave, and the north invaded.
We hold these issues very strongly and very deeply. Most northern folks do not understand. We were a conquered and oppressed and humiliated people during reconstruction. A carpetbagger is worse than any racial epithet. It is the worst form of scoundrel. The first republican gubernatorial administration of Texas to be unseated in the election years after the war had to be forced out at gunpoint. They had control, illegal possession, and they did not want to leave.
Now do not think that anyone can call my ancestors treasonous and come away without my vehement response. The Supreme Court advised against the prosecution of Jefferson Davis for treason, because they knew the case would be lost, and the proof would have upset the entire legality of the war. This is history.
The north had the draft riots, and I do not believe the south had the draft. By the way, I will argue for my ancestors until the day my own great great grandchildren die.